CBO examined three options under which Fannie Mae and Freddie Mac would provide principal forgiveness to certain distressed borrowers—specifically, to borrowers who are eligible or could become eligible for the Home Affordable Modification Program (HAMP). Such borrowers represent about 4 percent of all those with mortgages involving Fannie Mae or Freddie Mac, CBO estimates. The options would reduce the amount owed by borrowers to as low as 115 percent (through the HAMP Principal Reduction Alternative), 100 percent, and 90 percent, respectively, of the value of their homes. Any gain or loss arising from the way the distressed mortgages are handled by Fannie Mae and Freddie Mac under the options would ultimately accrue to taxpayers because, in CBO’s judgment, the federal government is now the effective owner of those enterprises. CBO finds that all three options would probably result in small savings to the government, slightly reduce mortgage foreclosure and delinquency rates, and slightly boost overall economic growth. Designing a program that affected a larger number of borrowers and had a greater impact on the housing market and the economy would require a significant departure from HAMP’s current eligibility rules.